Retainer Panel for a Vacuum Cleaner Bag, with Seal

ABSTRACT

The present invention provides a holding plate for a vacuum cleaner filter bag, comprising a base plate made of a plastic and having a passage opening formed therein, and a sealing membrane made of an elastic plastic material, which covers the passage opening and which is connected to the base plate, wherein the sealing membrane has a slit in the area of the passage opening, wherein the sealing membrane is, at least sectionwise, provided with a thickened area along the slit.

The present invention relates to a holding plate for a vacuum cleaner filter bag.

Conventional vacuum cleaner filter bags usually comprise a holding plate connected to the filter material of the bag in the area of the bag inlet opening. The holding plate serves to fasten the vacuum cleaner filter bag in the dust collection chamber of a vacuum cleaner, where the holding plate is inserted e.g. into a holder, which is provided there, and fixed in this way.

The holding plate has a passage opening, which is in alignment with the inlet opening in the bag wall and through which a sucked-in air current enters the vacuum cleaner filter bag during operation. To this end, a connection piece of the vacuum cleaner is inserted into the passage opening of the holding plate, so that the sucked-in air current can thus enter the vacuum cleaner filter bag, where the dust carried along with the air current is separated.

For providing a seal between the connection piece and the holding plate and the filter bag, respectively, the passage opening of the holding plate may be provided with an annular seal made of an elastic material. Such seals are known e.g. from DE 10 2010 060 353, DE 10 2007 062 028, DE 10 2008 041 227, EP 2 044 874 or DE 102 03 460.

The prior art additionally describes sealing elements which are able to close the passage opening of the holding plate, e.g. when the vacuum cleaner filter bag is removed from the vacuum cleaner. Teachings to this effect are disclosed e.g. in DE 20 2014 100 563, FR 2,721,188, DE 10 2007 057 170, DE 9016893, DE 8811821 and USD 600,868.

Closure devices for the passage openings of holding plates are additionally described in DE 20 2013 001 096, DE 10 2006 055 890, EP 0 758 209, DE 10 2011 105 384, DE 9101981, DE 10 2014 109 596, DE 20 2011 052 208, EP 2 123 206, DE 296 15 163, EP 1 137 360, DE 10 2012 012 999, DE 20 2013 100 862, DE 10 2008 046 200, DE 10 2006 037 456, DE 20 2008 004 733, CH 483 247, EP 1 480 545, EP 1 628 582, DE 10 2011 008 117, DE 20 2015 101 218and EP 1 480 545.

Taking this prior art as a basis, it is the object underlying the present invention to provide a holding plate for a vacuum cleaner filter bag, which is easy to manufacture and which provides a reliable closing function for the passage opening. This object is achieved by the subject matter of claim 1.

According to the present invention, a holding plate for a vacuum cleaner filter bag is provided, which comprises:

-   -   a base plate made of a plastic and having a passage opening         formed therein, and     -   a sealing membrane made of an elastic plastic material, which         covers the passage opening and which is connected to the base         plate,     -   wherein the sealing membrane has a slit in the area of the         passage opening, and     -   wherein the sealing membrane is, at least sectionwise, provided         with a thickened area along the slit.

Since the sealing membrane covers the passage opening, the passage opening of the holding plate is closed in this way in the case of a ready-made vacuum cleaner filter bag—e.g. in the removed condition of the vacuum cleaner filter bag. During operation, when the vacuum cleaner filter bag is inserted in the dust collection chamber of a vacuum cleaner, the connector of the vacuum cleaner (connection piece) enters the passage opening, whereby the latter is (mechanically) opened. In particular, the sealing membrane is opened due to the slit and stretched at least in certain areas thereof. This results not only in the formation of an inlet opening for a sucked-in air current but also in a sealing effect between the connection piece and the holding plate. When the connection piece is pulled out of the passage opening, the sealing membrane reassumes its original shape due to the elastic plastic material, i.e. it returns to its initial position or position of rest, so that the passage opening will be closed. The passage opening may be substantially circular.

The thickened area along the slit leads to an advantageous stabilization of the sealing membrane in the area of the slit and increases the restoring force. In this way, the sealing membrane will reliably return to its position of rest, when the connection piece has been pulled out and removed, and thus close the passage opening in a reliable manner. In the region of the thickened area, the sealing membrane has a larger thickness and a higher basis weight than in the other regions of the sealing membrane.

The thickened area may be provided along the slit sectionwise, i.e. along individual (separate) sections thereof, or over substantially the entire length of the slit. The sealing membrane may have a thickened area, at least sectionwise, only on one side or on both sides of the slit.

The thickened area may be configured in the form of a bead. Thus, the thickened area is configured as a thickened area of the plastic material as such. In other words, the sealing membrane and the thickened areas are formed integrally with one another and are made of the same material throughout; the thickened area is part of the sealing membrane. Hence, the thickened area leads to an elevation in the sealing membrane in this region. In particular, the sealing membrane may be configured as a single-layer component. The sealing membrane can be produced with little effort and at low cost in this way.

The sealing membrane may have two or more slits, the sealing membrane being—as described above—provided with a thickened area along one slit, a plurality of slits or all the slits sectionwise or over substantially the entire length of the latter. The thickened areas along two or a plurality of slits may be configured identically or differently.

In the case of a plurality of slits, each slit may have the characteristics described, independently of the other slits.

The provision of two or more slits allows the sealing membrane to be opened more easily and has the effect that it will reliably return to the initial position or the position of rest, when the connection piece is removed. When a plurality of slits is provided, the sealing membrane will not be excessively stretched in any area thereof, and this leads to less stress on the material.

When two or more slits are provided, at least two of the slits may intersect. The arrangement of the slits may here be substantially T-shaped, cross-shaped or star-shaped. Such slit arrangements reduce the stress on the material when the sealing membrane is opened; simultaneously, it can be guaranteed that the sealing membrane will reliably return to the initial position, when the connection piece is removed. The point of intersection of two intersecting slits can be arranged at a distance from the center of the sealing membrane corresponding to not more than 90%, preferably not more than 80% of the radius of the sealing membrane. In the case of cross-shaped or star-shaped slit arrangements, the point of intersection can especially be located at the center of the sealing membrane.

Each slit may be straight or curved. When a plurality of slits are provided, they may have identical or different shapes and/or dimensions.

Each slit may have a length corresponding to at least 50%, in particular at least 75%, of the diameter of the passage opening.

However, the slits may, but need not, be perpendicular to one another. They may extend at an angle of at least 45°, preferably at least 70°, to one another at the point of intersection. This applies especially also to arrangements in which the slits are arranged in a T-shaped, cross-shaped or star-shaped mode.

One, a plurality of or all the slits may be enlarged in width at one end or at both ends thereof. This enlargement may have a rounded shape, e.g. a circular shape. The enlargement reduces the risk of tearing of the sealing membrane at the slit ends. The enlargement can have a maximum diameter of not more than 8 mm, in particular of not more than 6 mm, especially of not more than 4 mm.

In all these configurations, the respective thickened areas may be configured as described. In particular, the thickened area may also be provided partially or fully along one, a plurality of or all the enlargements at the ends of the slits.

The sealing membrane may have a Shore A hardness of 30to 85. This allows a reliable sealing of the connection piece, without an excessive amount of force being required for inserting and removing the connection piece.

The elastic plastic material of the sealing membrane may be a thermoplastic (TPE) or a liquid silicone rubber (LSR). These materials exhibit a particularly advantageous restoring behavior. This means that, when the connection piece is removed from the passage opening, the sealing membrane, when made of these materials, will reassume its original shape in a particularly advantageous manner; the stretched areas contract and return to their initial position. The term “thermoplastic elastomer” is used according to the standard DIN EN ISO 18064:2014 and comprises in particular TPA, TPC, TPO, TPS, TPU, TPV and TPZ.

The sealing membrane may be an injection molded part. An injection-molded sealing membrane can be produced easily, at a reasonable price and reliably.

The sealing membrane may comprise a corrugated area. Such a corrugated structure reduces the risk of overstretching the material in use, i.e. when a connection piece is inserted into the passage opening. When a connection piece is inserted, the corrugated areas will first change to a flat state, so that the actual stretching of the material will only take place in a subsequent stage. The risk of exceeding the elasticity limit can be reduced in this way.

The corrugated areas may especially be formed in a circumferential direction along the edge of the passage opening of the base plate; they may be formed parallel to the edge. These areas are usually stretched most during insertion of the connection piece. In such a configuration, adjoining wave crests or troughs follow one another other in a circumferential direction (parallel to the edge of the opening).

The sealing membrane may be curved, in particular in a radial direction. In other words, the sealing membrane is, in its initial position, not located in a plane parallel to the plane of the passage opening provided in the base plate. Instead, it may curved perpendicular to the plane of the passage opening (e.g. in the direction of the passage opening or in a direction opposite thereto, or in the direction of the bag interior or in a direction facing away from the bag). In an, especially circular, area around the center of the sealing membrane and of the passage opening, respectively, the sealing membrane may exhibit a curvature. The extremum (the highest and the lowest point) of the sealing membrane may here be located especially at the center (of the passage opening). Such a curvature of the sealing membrane leads to an easier and more reliable closing, when the connection piece is removed.

The sealing membrane may have a uniform thickness outside the thickened area, i.e. in the non-thickened areas. In other words, the sealing membrane has the same thickness everywhere, except for the thickened areas. This thickness of the non-thickened areas can be determined e.g. at the edge of the passage opening.

The thickness of the sealing membrane may be at least 0.10 mm, preferably 0.30 mm, and/or not thicker than 1.0 mm, preferably not thicker than 0.60 mm. These thicknesses relate to the non-thickened areas. The thickness is here determined in accordance with the standard DIN 53370:2006-11, point 4.1.2, method P (spherical calotte R30, contact pressure 0.1 N).

The thickness of the sealing membrane may be increased by at least 20%, preferably by at least 50%, (relative to the other, non-thickened areas), in the region of the thickened area. This leads to an advantageous stabilization and provision of a sufficiently high restoring force. The thickened area may have a height of 0.1-0.4 mm, starting from the surface of the sealing membrane.

The sealing membrane may have, in the region of the thickened area, a thickness of at least 0.11 mm, preferably at least 0.40 mm, and/or a maximum thickness of 1.20 mm, in particular a maximum thickness of 0.70 mm.

With these values, a sealing membrane is provided, which allows sealing of the connection piece with respect to the base plate as well as reliable closing.

The thickened area may be configured such that it extends to only one side of the sealing membrane or to both sides of the sealing membrane. If the thickened area is configured such that it extends to only one side, the sealing membrane has a flat surface on the opposite side thereof; the sealing membrane has an elevation or a bead only on the side exhibiting the thickened area.

The thickened area has in particular an elongate shape (i.e. its length exceeds its width) or a linear shape and extends, sectionwise or fully, parallel to the slit, in particular also parallel to an enlargement at the end of a slit. The thickened area may be formed in a region along the slit, the region having a maximum width of 5 mm, in particular a maximum width of 3 mm. The region along the slit may directly adjoin the slit, i.e. it may be delimited by an edge of the slit.

The thickened area itself may have a width of at least 0.10 mm, preferably at least 0.20 mm, and/or a maximum width of 0.40 mm, preferably a maximum width of 0.30 mm. The width of the thickened area refers to the width of the area in which the thickness of the sealing membrane is larger than in the other, non-thickened areas (e.g. at the edge of the passage opening); what is meant is therefore the width of the bead.

These widths ensure, on the one hand, that the desired stabilization of the sealing membrane is accomplished and avoid, on the other hand, an excessively high stiffness of the sealing membrane.

The thickened area may have a constant or a variable thickness along the slit. The constant or the variable thickness may especially be chosen depending on the geometry and/or the position of the slit. For example, the thickness may be largest in the middle of the slit and decrease towards the two ends of the latter.

The sealing membrane may be welded to the base plate or injection molded onto the latter. This allows a reliable connection even under load during operation. In addition, the holding plate can be produced easily and at a reasonable price in this way.

The present invention additionally provides a vacuum cleaner filter bag, comprising:

-   -   a bag wall consisting of a filter material with an inlet         opening,     -   a base plate made of a plastic and having a passage opening         formed therein, and     -   a sealing membrane made of an elastic plastic material and         covering the passage opening,     -   wherein the sealing membrane is connected to the base plate         and/or the bag wall,     -   wherein the sealing membrane has a slit in the area of the         passage opening, and     -   wherein the sealing membrane is, at least sectionwise, provided         with a thickened area along the slit.

In this way, in particular a vacuum cleaner filter bag comprising one of the above-described holding plates is provided. According to an alternative embodiment, the sealing membrane is connected to the bag wall. It may here be arranged on the outside of or in the interior of the bag.

The vacuum cleaner filter bag may in particular comprise a single-layer or multi-layer bag wall of filter material. The filter material may especially be a non-woven fabric. The vacuum cleaner filter bag may be a flat bag or it may have a block bottom shape. A flat bag is defined by two sidewalls of filter material, which are connected to one another along their peripheral edges (e.g. by means of a welding or bonding). One of the two sidewalls may have provided therein the bag filling opening or inlet opening. The lateral surfaces or sidewalls may each have a rectangular basic shape. Each sidewall may comprise one or a plurality of layers of a non-woven and/or of a nonwoven fabric.

The holding plate may be welded to the bag wall of the vacuum cleaner filter bag.

Other features and advantages will be described hereinafter with reference to the figures, in which

FIG. 1 shows a schematic top view of a holding plate with a sealing membrane;

FIG. 2 shows a schematic cross-sectional view of a holding plate with a sealing membrane;

FIG. 3 shows a further schematic cross-sectional view of a holding plate with a sealing membrane; and

FIG. 4 shows a schematic top view of a holding plate with a sealing membrane.

FIG. 1 illustrates schematically a top view of a holding plate 1 comprising a base plate 2 made of plastic, e.g. polypropylene (PP) or polyethylene terephthalate (PET), in particular recycled PET (rPET). During operation, this holding plate 1 is inserted (as part of a vacuum cleaner filter bag) into a holder in the interior of a dust collection chamber of a vacuum cleaner, so as to hold a vacuum cleaner filter bag in this way. The base plate has formed therein a passage opening 3, which is fully covered by a sealing membrane 4; in particular, no central opening for a connection piece is provided. The sealing membrane is of the single-layer type and consists of a thermoplastic elastomer (TPE) or of liquid silicone rubber (LSR).

The sealing membrane 4 has two slits 5 in the area of the passage opening 3. In the example shown, the two slits intersect in a T-shaped configuration. One of the two slits extends essentially perpendicular to the other slit. At the ends of the two slits, the slits widen slightly, thus forming (small) circular holes that prevent the sealing membrane from tearing at the slit ends. These holes have a diameter in the range of 1-8 mm.

Other than in the example shown, the slits may also extend relative to each other at an angle unequal to 90°, e.g. at an angle of 45°. One of the two slits or both slits may be curved, e.g. U-shaped or wave-shaped.

At the position of rest or initial position shown, the opposite edges of a slit abut on each other, so that the passage opening 3 is closed by the sealing membrane. When the holding plate (as part of a vacuum cleaner filter bag) has been inserted into a dust collection chamber of a vacuum cleaner, a connection piece of a vacuum cleaner is inserted into the passage opening 3, whereby the sealing membrane 4 is deflected downwards (into the interior of the vacuum cleaner filter bag) and the slits are widened. The connection piece may be provided e.g. in the cover of the vacuum cleaner and enter the passage opening during closing of the cover. As a result, the sealing membrane opens in the passage opening; in so doing, the sealing membrane surrounds the connection piece and seals the latter. When the sealing membrane is being deflected, it is stretched along the circumference of the passage opening 3, in particular in the peripheral area thereof.

In addition to the slits, the sealing membrane has thickened areas 6. These thickened areas 6 are elongate or linear in shape and extend along and parallel to the respective slit 5. Three of the thickened areas are substantially straight. In addition, a further (curved) thickened area 6 is provided parallel to each of the enlargements at the end of the slits, whereby the risk of tearing is reduced still further at these locations.

The sealing membrane 4 has, fundamentally, a uniform and constant thickness in a range of from 0.1 mm to 0.8 mm across its entire area. This thickness can be measured e.g. in the edge area of the passage opening 3, in particular directly at the edge of the passage opening. In the region of the thickened areas 6, the thickness increases, so that a bead is formed. This bead has a height of 0.1-0.4 mm, starting from the surface of the sealing membrane 4. The maximum thickness of the sealing membrane in the thickened area thus lies in a range of 0.2 to 1.2 mm.

The line-shaped thickened areas reinforce the sealing membrane in this region. Due to such reinforcing, the sealing membrane is stabilized and has an increased restoring force in these regions. Due to this fact, the sealing membrane will reliably return to its position of rest, in which the passage opening 3 is closed, when the connection piece has been removed. It follows that, when the cover of the vacuum cleaner is opened and the connection piece is thus removed from the passage opening, the vacuum cleaner bag will close and can be disposed of hygienically.

In the example shown, the vertical slit has a thickened area on both sides thereof (i.e. on the left and on the right). In the case of the horizontal slit, only one thickened area is provided on one side. In addition, thickened areas are arranged at three slit ends.

Alternative embodiments are, however, possible as well. All the thickened areas are located on the same side of the sealing membrane. The thickened areas may have a constant thickness/height or a variable height over their entire length.

FIG. 2 shows a schematic cross-sectional view of a holding plate 1, comprising a base plate 2 with a passage opening 3 and a sealing membrane 4 covering the passage opening 3. The holding plate 1 is here welded to the bag wall 7 of a vacuum cleaner filter bag. The bag wall 7 comprises one or a plurality of layers of a non-woven fabric.

In the example illustrated, the base plate 2, the sealing membrane 4 and the bag wall 7 are welded to one another. The holding plate is here typically welded to the bag wall at first positions; the sealing membrane is welded to the holding plate and/or the bag wall at other, second positions.

In the example shown, the sealing membrane 4 is arranged between the base plate 2 and the bag wall 7. Alternatively, the sealing membrane may also be provided on the side of the base plate facing away from the bag wall. As a further possibility, the sealing membrane may also be fixed (e.g. welded) to the bag wall inside the bag.

During the production/making of the vacuum cleaner bag, the sealing membrane may either first be connected to the base plate of the holding plate; subsequently, this holding plate is connected to the bag wall. Alternatively, the sealing membrane may first be connected to the bag wall (in the interior of or on the outside of the bag); subsequently, the base plate is connected to the bag wall. These connections may be established in the form of adhesive and/or (ultrasonic) welded connections.

In the area of the passage opening 3, FIG. 2 shows a slit 5 in the sealing membrane 4, a bead-shaped thickened area 6 being provided on either side of the slit. In this example, both thickened areas are formed only towards one side of the sealing membrane 4, viz. towards the top. Alternatively, the thickened areas may also be formed towards the other side or towards both sides.

In the example shown in FIG. 2, the sealing membrane, when occupying its position of rest or initial position, is located in a plane parallel to the passage opening 3. When a connection piece has been pulled out, the sealing membrane will reassume its original shape.

FIG. 3 shows an alternative embodiment, in the case of which the sealing membrane 4 is curved in a radial direction, when occupying its position of rest. This means that, in the example shown, it is curved in the direction of the passage opening 3. In an area around the passage opening center through which the slit 5 extends, the curvature is convex (when the passage opening is seen in a top view from outside). In this embodiment, the bead-shaped thickened areas 6 are formed on the side of the sealing membrane 4 facing away from the passage opening, i.e. they are directed towards the interior of the bag.

FIG. 4 shows a schematic top view of an embodiment of a holding plate 1, in which the sealing membrane has provided therein two slits 5 arranged in a cross shape. Along these slits 5, thickened areas 6 are provided sectionwise. These thickened areas do not extend continuously over the entire length of the respective slit, but they are configured separately.

In addition, the sealing membrane 4 has four corrugated areas 8. The corrugated structure is here configured such that it extends in a circumferential direction, as shown in a similar manner e.g. in DE 86 22 890. In the areas 8, the sealing membrane 4 is thus similar to crepe paper or a corrugated cardboard. Due to the corrugated structure, additional material is provided for the sealing membrane 4 in these areas.

When a connection piece is inserted into the passage opening 3, the sealing membrane first changes to a smooth condition in the originally corrugated areas, i.e. it is pulled smooth, and only afterwards it will be stretched there. This leads to less stress on the sealing membrane and thus to reliable closing even after a comparatively long period of time.

It goes without saying that the features disclosed in the various figures and examples may also be combined in an arbitrary different way. In addition, also other configurations for the slits and/or thickened areas—as described above —are possible. 

1. A holding plate for a vacuum cleaner filter bag, the holding plate comprising: a base plate made of a plastic and having a passage opening formed therein, and a sealing membrane made of an elastic plastic material, which covers the passage opening and which is connected to the base plate, wherein the sealing membrane has a slit in an area of the passage opening, wherein the sealing membrane is, at least sectionwise, provided with a thickened area along the slit.
 2. The holding plate according to claim 1, wherein the thickened area comprises a bead.
 3. The holding plate according to claim 1, wherein the sealing membrane has two or more slits, the sealing membrane being, at least sectionwise, provided with a thickened area along one slit, a plurality of slits or all the slits.
 4. The holding plate according to claim 1, wherein the elastic plastic material is a thermoplastic or a liquid silicone rubber.
 5. The holding plate according to claim 1, wherein the sealing membrane comprises a corrugated area.
 6. The holding plate according to claim 1, wherein the sealing membrane is curved.
 7. The holding plate according to claim 1, wherein a thickness of the sealing membrane is increased by at least 20% in the region of the thickened area.
 8. The holding plate according to claim 1, wherein the sealing membrane has a thickness of at least 0.10 mm, or a maximum thickness of 1.0 mm.
 9. The holding plate according to claim 1, wherein the sealing membrane has, in the region of the thickened area, a thickness of at least 0.12 mm, or a maximum thickness of 1.20 mm.
 10. The holding plate according to claim 1, wherein the thickened area extends to only one side of the sealing membrane or to both sides of the sealing membrane.
 11. The holding plate according to claim 1, wherein the thickened area has a width of at least 0.10 mm, preferably at least 0.20 mm, and/or a maximum width of 0.40 mm, preferably a maximum width of 0.30 mm.
 12. The holding plate according to claim 1, wherein, outside the thickened area, the sealing membrane has a uniform thickness.
 13. The holding plate according to claim 1, wherein the thickened area has a constant or a variable thickness along the slit.
 14. The holding plate according to claim 1, wherein the sealing membrane is welded to the base plate or injection molded onto the base plate.
 15. A vacuum cleaner filter bag comprising a bag wall consisting of a filter material with an inlet opening, a base plate made of a plastic and having a passage opening formed therein, and a sealing membrane made of an elastic plastic material and covering the passage opening, wherein the sealing membrane is connected to the base plate or the bag wall, wherein the sealing membrane has a slit in an area of the passage opening, and wherein the sealing membrane is, at least sectionwise, provided with a thickened area along the slit.
 16. The holding plate according to claim 1, wherein a thickness of the sealing membrane is increased by at least 50% in the region of the thickened area.
 17. The holding plate according to claim 1, wherein the sealing membrane has a thickness of at least 0.30 mm or a maximum thickness of 0.60 mm.
 18. The holding plate according to claim 1, wherein the sealing membrane has, in the region of the thickened area, a thickness of at least 0.40 mm or a maximum thickness of 0.70 mm.
 19. The holding plate according to claim 1, wherein the thickened area has a width of at least 0.20 mm or a maximum width of 0.30 mm. 